I have been looking into converting the Drupal 7 conditional fields module to Backdrop, as I really need a module like this for a project I am working on.
However I am a bit stuck, because the Drupal 7 module joins the field_config_instance table, but this table doesn't exist in backdrop.
$select = db_select('conditional_fields', 'cf')
->fields('cf', array('id', 'options'))
$fci_depende = $select->join('field_config_instance', 'fci_dependee', 'cf.dependee = fci_dependee.id');
$fci_dependent = $select->join('field_config_instance', 'fci_dependent', 'cf.dependent = fci_dependent.id');
$select->addField($fci_depende, 'field_name', 'dependee');
$select->addField($fci_dependent, 'field_name', 'dependent');
I guess I could just create that table, but also the module relies on Field ID's, but these does not seem to exist in Backdrop. They do not exist in this function as they do in Drupal 7:
$instances = field_info_instances($entity_type, $bundle_name);
I am primarily a frontend developer, so if anyone have an idea or suggestion on how to overcome these issues, that could point me in the right direction, it would be much appriciated :)